The present invention relates to an electronic autoclave cycle sensor. Instruments used in surgery must be cleaned and sterilized after each use to eliminate microorganisms and viruses to prevent infection. While many sterilization methods are used, the most effective, lowest cost, quickest and most available method is application of steam in an autoclave. However, an autoclave provides a hostile environment causing wear on surgical instruments that, over time, requires maintenance to avoid instrument failure.
Often, manufacturers set prescribed design goals for their instruments including warranting the minimum number of autoclave cycles that the instrument is designed to withstand. Accordingly, it is helpful for the user to know how many autoclave cycles his or her instruments have undergone so that appropriate maintenance can be scheduled. Additionally, manufacturers of instruments are interested in knowing whether an instrument has been subjected to a sufficient number of autoclave cycles so as to render the instrument warranty void.
U.S. Pat. No. 3,450,489 to Fay discloses a sterilization control means that includes a thermal responsive signal producing means enclosed within wrapped articles to be sterilized. The signal means produces and transmits a control signal from within the bundle which is used to control the sterilization operation to ensure thorough sterilization of the wrapped articles. Fay fails to teach or suggest any means for counting the number of cycles to which an instrument has been subjected nor does Fay teach or suggest any magnetic means to sense the number of autoclave cycles to which an instrument has been subjected.
U.S. Pat. No. 3,568,627 to Sellenger et al. discloses a combined record card and sterilization indicator including a portion of the record that changes colors to indicate that sterilization has taken place. Sellenger et al. fail to teach or suggest any magnetic means for counting the number of autoclave cycles to which an instrument has been subjected.
U.S. Pat. No. 4,235,842 to Thomas et al. discloses a temperature cycle indicating means for a sterilizer unit that is designed to count the number of cycles of sterilization to which contact lenses have been subjected. Thomas et al. fail to teach or suggest the use of magnetic means to perform such function.
U.S. Pat. No. 4,850,716 to Baker et al. discloses a remotely detectable sterilization monitor that detects conditions indicative of sterilization through the melting of compounds. Magnetic material of high permeability and low coercivity create two distinct magnetic states. When the magnetic material melts responsive to exposure to high temperature, magnetized material is released and moves away from its original location due to spring tension from adjacent magnetic material thereby decreasing the bias effect of the first-mentioned magnetic material. When interrogation is conducted by an external force field, this separation may be detected. The present invention differs from the teachings of Baker et al. as contemplating use of magnetic sensing means for sensing a magnetic field and, responsive thereto, signaling that a cycle of sterilization has taken place.
U.S. Pat. No. 5,313,935 to Kortenbach et al. discloses an apparatus for counting the number of times a surgical instrument has been used. Kortenbach et al. employ a bi-metallic element that moves responsive to temperature change to cause a ratchet wheel to be advanced through engagement by an inwardly extending tooth to advance an indicator to show that one sterilization cycle has taken place. Kortenbach et al. fail to teach or suggest the use of magnetic sensing means.